ddp.c

linux 内核源代码

		goto out;
	}

	/* if IP over DDP is not selected this code will be optimized out */
	if (is_ip_over_ddp(skb))
		return handle_ip_over_ddp(skb);
	/*
	 * Which socket - atalk_search_socket() looks for a *full match*
	 * of the <net, node, port> tuple.
	 */
	tosat.sat_addr.s_net  = ddp->deh_dnet;
	tosat.sat_addr.s_node = ddp->deh_dnode;
	tosat.sat_port	      = ddp->deh_dport;

	sock = atalk_search_socket(&tosat, atif);
	if (!sock) /* But not one of our sockets */
		goto freeit;

	/* Queue packet (standard) */
	skb->sk = sock;

	if (sock_queue_rcv_skb(sock, skb) < 0)
		goto freeit;
out:
	return 0;
freeit:
	kfree_skb(skb);
	goto out;
}

/*
 * Receive a LocalTalk frame. We make some demands on the caller here.
 * Caller must provide enough headroom on the packet to pull the short
 * header and append a long one.
 */
static int ltalk_rcv(struct sk_buff *skb, struct net_device *dev,
		     struct packet_type *pt, struct net_device *orig_dev)
{
	if (dev->nd_net != &init_net)
		goto freeit;

	/* Expand any short form frames */
	if (skb_mac_header(skb)[2] == 1) {
		struct ddpehdr *ddp;
		/* Find our address */
		struct atalk_addr *ap = atalk_find_dev_addr(dev);

		if (!ap || skb->len < sizeof(__be16) || skb->len > 1023)
			goto freeit;

		/* Don't mangle buffer if shared */
		if (!(skb = skb_share_check(skb, GFP_ATOMIC)))
			return 0;

		/*
		 * The push leaves us with a ddephdr not an shdr, and
		 * handily the port bytes in the right place preset.
		 */
		ddp = (struct ddpehdr *) skb_push(skb, sizeof(*ddp) - 4);

		/* Now fill in the long header */

		/*
		 * These two first. The mac overlays the new source/dest
		 * network information so we MUST copy these before
		 * we write the network numbers !
		 */

		ddp->deh_dnode = skb_mac_header(skb)[0];     /* From physical header */
		ddp->deh_snode = skb_mac_header(skb)[1];     /* From physical header */

		ddp->deh_dnet  = ap->s_net;	/* Network number */
		ddp->deh_snet  = ap->s_net;
		ddp->deh_sum   = 0;		/* No checksum */
		/*
		 * Not sure about this bit...
		 */
		/* Non routable, so force a drop if we slip up later */
		ddp->deh_len_hops = htons(skb->len + (DDP_MAXHOPS << 10));
	}
	skb_reset_transport_header(skb);

	return atalk_rcv(skb, dev, pt, orig_dev);
freeit:
	kfree_skb(skb);
	return 0;
}

static int atalk_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
			 size_t len)
{
	struct sock *sk = sock->sk;
	struct atalk_sock *at = at_sk(sk);
	struct sockaddr_at *usat = (struct sockaddr_at *)msg->msg_name;
	int flags = msg->msg_flags;
	int loopback = 0;
	struct sockaddr_at local_satalk, gsat;
	struct sk_buff *skb;
	struct net_device *dev;
	struct ddpehdr *ddp;
	int size;
	struct atalk_route *rt;
	int err;

	if (flags & ~(MSG_DONTWAIT|MSG_CMSG_COMPAT))
		return -EINVAL;

	if (len > DDP_MAXSZ)
		return -EMSGSIZE;

	if (usat) {
		if (sock_flag(sk, SOCK_ZAPPED))
			if (atalk_autobind(sk) < 0)
				return -EBUSY;

		if (msg->msg_namelen < sizeof(*usat) ||
		    usat->sat_family != AF_APPLETALK)
			return -EINVAL;

		/* netatalk doesn't implement this check */
		if (usat->sat_addr.s_node == ATADDR_BCAST &&
		    !sock_flag(sk, SOCK_BROADCAST)) {
			printk(KERN_INFO "SO_BROADCAST: Fix your netatalk as "
					 "it will break before 2.2\n");
#if 0
			return -EPERM;
#endif
		}
	} else {
		if (sk->sk_state != TCP_ESTABLISHED)
			return -ENOTCONN;
		usat = &local_satalk;
		usat->sat_family      = AF_APPLETALK;
		usat->sat_port	      = at->dest_port;
		usat->sat_addr.s_node = at->dest_node;
		usat->sat_addr.s_net  = at->dest_net;
	}

	/* Build a packet */
	SOCK_DEBUG(sk, "SK %p: Got address.\n", sk);

	/* For headers */
	size = sizeof(struct ddpehdr) + len + ddp_dl->header_length;

	if (usat->sat_addr.s_net || usat->sat_addr.s_node == ATADDR_ANYNODE) {
		rt = atrtr_find(&usat->sat_addr);
	} else {
		struct atalk_addr at_hint;

		at_hint.s_node = 0;
		at_hint.s_net  = at->src_net;

		rt = atrtr_find(&at_hint);
	}
	if (!rt)
		return -ENETUNREACH;

	dev = rt->dev;

	SOCK_DEBUG(sk, "SK %p: Size needed %d, device %s\n",
			sk, size, dev->name);

	size += dev->hard_header_len;
	skb = sock_alloc_send_skb(sk, size, (flags & MSG_DONTWAIT), &err);
	if (!skb)
		return err;

	skb->sk = sk;
	skb_reserve(skb, ddp_dl->header_length);
	skb_reserve(skb, dev->hard_header_len);
	skb->dev = dev;

	SOCK_DEBUG(sk, "SK %p: Begin build.\n", sk);

	ddp = (struct ddpehdr *)skb_put(skb, sizeof(struct ddpehdr));
	ddp->deh_len_hops  = htons(len + sizeof(*ddp));
	ddp->deh_dnet  = usat->sat_addr.s_net;
	ddp->deh_snet  = at->src_net;
	ddp->deh_dnode = usat->sat_addr.s_node;
	ddp->deh_snode = at->src_node;
	ddp->deh_dport = usat->sat_port;
	ddp->deh_sport = at->src_port;

	SOCK_DEBUG(sk, "SK %p: Copy user data (%Zd bytes).\n", sk, len);

	err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
	if (err) {
		kfree_skb(skb);
		return -EFAULT;
	}

	if (sk->sk_no_check == 1)
		ddp->deh_sum = 0;
	else
		ddp->deh_sum = atalk_checksum(skb, len + sizeof(*ddp));

	/*
	 * Loopback broadcast packets to non gateway targets (ie routes
	 * to group we are in)
	 */
	if (ddp->deh_dnode == ATADDR_BCAST &&
	    !(rt->flags & RTF_GATEWAY) && !(dev->flags & IFF_LOOPBACK)) {
		struct sk_buff *skb2 = skb_copy(skb, GFP_KERNEL);

		if (skb2) {
			loopback = 1;
			SOCK_DEBUG(sk, "SK %p: send out(copy).\n", sk);
			if (aarp_send_ddp(dev, skb2,
					  &usat->sat_addr, NULL) == -1)
				kfree_skb(skb2);
				/* else queued/sent above in the aarp queue */
		}
	}

	if (dev->flags & IFF_LOOPBACK || loopback) {
		SOCK_DEBUG(sk, "SK %p: Loop back.\n", sk);
		/* loop back */
		skb_orphan(skb);
		if (ddp->deh_dnode == ATADDR_BCAST) {
			struct atalk_addr at_lo;

			at_lo.s_node = 0;
			at_lo.s_net  = 0;

			rt = atrtr_find(&at_lo);
			if (!rt) {
				kfree_skb(skb);
				return -ENETUNREACH;
			}
			dev = rt->dev;
			skb->dev = dev;
		}
		ddp_dl->request(ddp_dl, skb, dev->dev_addr);
	} else {
		SOCK_DEBUG(sk, "SK %p: send out.\n", sk);
		if (rt->flags & RTF_GATEWAY) {
		    gsat.sat_addr = rt->gateway;
		    usat = &gsat;
		}

		if (aarp_send_ddp(dev, skb, &usat->sat_addr, NULL) == -1)
			kfree_skb(skb);
		/* else queued/sent above in the aarp queue */
	}
	SOCK_DEBUG(sk, "SK %p: Done write (%Zd).\n", sk, len);

	return len;
}

static int atalk_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
			 size_t size, int flags)
{
	struct sock *sk = sock->sk;
	struct sockaddr_at *sat = (struct sockaddr_at *)msg->msg_name;
	struct ddpehdr *ddp;
	int copied = 0;
	int offset = 0;
	int err = 0;
	struct sk_buff *skb = skb_recv_datagram(sk, flags & ~MSG_DONTWAIT,
						flags & MSG_DONTWAIT, &err);
	if (!skb)
		return err;

	/* FIXME: use skb->cb to be able to use shared skbs */
	ddp = ddp_hdr(skb);
	copied = ntohs(ddp->deh_len_hops) & 1023;

	if (sk->sk_type != SOCK_RAW) {
		offset = sizeof(*ddp);
		copied -= offset;
	}

	if (copied > size) {
		copied = size;
		msg->msg_flags |= MSG_TRUNC;
	}
	err = skb_copy_datagram_iovec(skb, offset, msg->msg_iov, copied);

	if (!err) {
		if (sat) {
			sat->sat_family      = AF_APPLETALK;
			sat->sat_port        = ddp->deh_sport;
			sat->sat_addr.s_node = ddp->deh_snode;
			sat->sat_addr.s_net  = ddp->deh_snet;
		}
		msg->msg_namelen = sizeof(*sat);
	}

	skb_free_datagram(sk, skb);	/* Free the datagram. */
	return err ? : copied;
}


/*
 * AppleTalk ioctl calls.
 */
static int atalk_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
	int rc = -ENOIOCTLCMD;
	struct sock *sk = sock->sk;
	void __user *argp = (void __user *)arg;

	switch (cmd) {
		/* Protocol layer */
		case TIOCOUTQ: {
			long amount = sk->sk_sndbuf -
				      atomic_read(&sk->sk_wmem_alloc);

			if (amount < 0)
				amount = 0;
			rc = put_user(amount, (int __user *)argp);
			break;
		}
		case TIOCINQ: {
			/*
			 * These two are safe on a single CPU system as only
			 * user tasks fiddle here
			 */
			struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
			long amount = 0;

			if (skb)
				amount = skb->len - sizeof(struct ddpehdr);
			rc = put_user(amount, (int __user *)argp);
			break;
		}
		case SIOCGSTAMP:
			rc = sock_get_timestamp(sk, argp);
			break;
		case SIOCGSTAMPNS:
			rc = sock_get_timestampns(sk, argp);
			break;
		/* Routing */
		case SIOCADDRT:
		case SIOCDELRT:
			rc = -EPERM;
			if (capable(CAP_NET_ADMIN))
				rc = atrtr_ioctl(cmd, argp);
			break;
		/* Interface */
		case SIOCGIFADDR:
		case SIOCSIFADDR:
		case SIOCGIFBRDADDR:
		case SIOCATALKDIFADDR:
		case SIOCDIFADDR:
		case SIOCSARP:		/* proxy AARP */
		case SIOCDARP:		/* proxy AARP */
			rtnl_lock();
			rc = atif_ioctl(cmd, argp);
			rtnl_unlock();
			break;
	}

	return rc;
}


#ifdef CONFIG_COMPAT
static int atalk_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
	/*
	 * All Appletalk ioctls except SIOCATALKDIFADDR are standard.  And
	 * SIOCATALKDIFADDR is handled by upper layer as well, so there is
	 * nothing to do.  Eventually SIOCATALKDIFADDR should be moved
	 * here so there is no generic SIOCPROTOPRIVATE translation in the
	 * system.
	 */
	return -ENOIOCTLCMD;
}
#endif


static struct net_proto_family atalk_family_ops = {
	.family		= PF_APPLETALK,
	.create		= atalk_create,
	.owner		= THIS_MODULE,
};

static const struct proto_ops SOCKOPS_WRAPPED(atalk_dgram_ops) = {
	.family		= PF_APPLETALK,
	.owner		= THIS_MODULE,
	.release	= atalk_release,
	.bind		= atalk_bind,
	.connect	= atalk_connect,
	.socketpair	= sock_no_socketpair,
	.accept		= sock_no_accept,
	.getname	= atalk_getname,
	.poll		= datagram_poll,
	.ioctl		= atalk_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl	= atalk_compat_ioctl,
#endif
	.listen		= sock_no_listen,
	.shutdown	= sock_no_shutdown,
	.setsockopt	= sock_no_setsockopt,
	.getsockopt	= sock_no_getsockopt,
	.sendmsg	= atalk_sendmsg,
	.recvmsg	= atalk_recvmsg,
	.mmap		= sock_no_mmap,
	.sendpage	= sock_no_sendpage,
};

SOCKOPS_WRAP(atalk_dgram, PF_APPLETALK);

static struct notifier_block ddp_notifier = {
	.notifier_call	= ddp_device_event,
};

static struct packet_type ltalk_packet_type = {
	.type		= __constant_htons(ETH_P_LOCALTALK),
	.func		= ltalk_rcv,
};

static struct packet_type ppptalk_packet_type = {
	.type		= __constant_htons(ETH_P_PPPTALK),
	.func		= atalk_rcv,
};

static unsigned char ddp_snap_id[] = { 0x08, 0x00, 0x07, 0x80, 0x9B };

/* Export symbols for use by drivers when AppleTalk is a module */
EXPORT_SYMBOL(aarp_send_ddp);
EXPORT_SYMBOL(atrtr_get_dev);
EXPORT_SYMBOL(atalk_find_dev_addr);

static char atalk_err_snap[] __initdata =
	KERN_CRIT "Unable to register DDP with SNAP.\n";

/* Called by proto.c on kernel start up */
static int __init atalk_init(void)
{
	int rc = proto_register(&ddp_proto, 0);

	if (rc != 0)
		goto out;

	(void)sock_register(&atalk_family_ops);
	ddp_dl = register_snap_client(ddp_snap_id, atalk_rcv);
	if (!ddp_dl)
		printk(atalk_err_snap);

	dev_add_pack(&ltalk_packet_type);
	dev_add_pack(&ppptalk_packet_type);

	register_netdevice_notifier(&ddp_notifier);
	aarp_proto_init();
	atalk_proc_init();
	atalk_register_sysctl();
out:
	return rc;
}
module_init(atalk_init);

/*
 * No explicit module reference count manipulation is needed in the
 * protocol. Socket layer sets module reference count for us
 * and interfaces reference counting is done
 * by the network device layer.
 *
 * Ergo, before the AppleTalk module can be removed, all AppleTalk
 * sockets be closed from user space.
 */
static void __exit atalk_exit(void)
{
#ifdef CONFIG_SYSCTL
	atalk_unregister_sysctl();
#endif /* CONFIG_SYSCTL */
	atalk_proc_exit();
	aarp_cleanup_module();	/* General aarp clean-up. */
	unregister_netdevice_notifier(&ddp_notifier);
	dev_remove_pack(&ltalk_packet_type);
	dev_remove_pack(&ppptalk_packet_type);
	unregister_snap_client(ddp_dl);
	sock_unregister(PF_APPLETALK);
	proto_unregister(&ddp_proto);
}
module_exit(atalk_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Alan Cox <[e-mail]>");
MODULE_DESCRIPTION("AppleTalk 0.20\n");
MODULE_ALIAS_NETPROTO(PF_APPLETALK);